The invention relates to a restraining system and, in particular, to a restraining system for a motor vehicle including a restraining device, which is activated in at least two stages, a sensor unit for sensing activation-relevant operating data, a control device for processing the activation-relevant operating data, and an ignition unit for driving the triggering units to activate the at least one restraining device.
Such restraining systems (which are known, for example, as an air bag system or as a seat belt system with a seat belt tightener or the like) for the protection of the occupants of a motor vehicle in the event of an accident have already become in the interim a standard feature in many vehicles. Typically, acceleration sensors, which are disposed in the vehicle, detect whether an abrupt delay of the vehicle, which is to be interpreted as a collision with an obstacle, has occurred. In the given case, an airbag in its folded state is filled, for example, with gas within a few fractions of a second by activating, or rather igniting, an ignition unit in order to intercept the body of an occupant and to avoid contact with harder parts of the vehicle.
Improved systems are in a position to fill, step-by-step, the airbag as a function of the size of the person and/or the magnitude of the accident. In this way, it is achieved that the airbag is inflated in such a manner that it is adapted to the situation (a child or an adult and/or a severe or mild accident) and that unnecessary milder injuries, caused by overfilling the airbag or filling the airbag too fast, are avoided. Such a system has already been described in the German patent document DE 101 02 646 A1.
The present invention is based on the problem of providing a restraining system that is intended for a vehicle and that ensures an improved protection of the occupants.
The invention solves this problem by providing an occupant restraint system for a motor vehicle including a restraining device, which is activated in at least two stages, a sensor unit for sensing activation-relevant operating data, a control device for processing the activation-relevant operating data, and an ignition unit for driving the triggering units to activate the at least one restraining device. At least two independently switched ignition units are provided such that if one ignition unit fails, the activation of the restraining device in at least one stage is guaranteed by the other ignition unit. The construction of the inventive restraining system, in which at least two different ignition units are assigned to each restraining device, to be activated step-by-step, for activating its different stages, ensures that, when one ignition unit fails, the restraining device (or rather each restraining device) to be activated is activated at least partly in at least one single stage by at least one other ignition unit.
In a preferred embodiment of the invention, each ignition unit exhibits a plurality of ignition end stages, whereby the individual ignition end stages are assigned to each ignition unit of a number of different restraining devices (in particular, of the same type—e.g., only airbags or only seat-belt systems). In an especially preferred embodiment, the invention relates to restraining systems in the form of airbag systems. As an alternative or in addition, however, other restraining systems, such as a seat-belt system with a seat belt tightener, are also envisioned.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.